This invention relates to jewelry rope chains and more particularly to a jewelry rope chain having a novel construction requiring less labor time for such construction.
Jewelry rope chains are a specific type of chain product formed by intertwining links in a particular manner whereby the result is a double helix configuration. Such jewelry rope chains are well known in the art and are generally formed of precious metal. Although the links can be formed of numerous shapes and configurations, the generally accepted classic jewelry rope chain is formed of an annular shaped link. Similarly, although numerous cross sectional shapes of the link wire are well known, the classic jewelry rope chain has been formed of round wire. In the case of solid rope chain, solid wire is utilized. In the case of a hollow rope chain, the wire is of tubular configuration. Such hollow links formed of the hollow tubular wire, can either be formed with a seam along the inner periphery of the link or can be seamless without such seam. The purpose of the seam being to permit removal of a core placed in the interior of the tubular wire to provide support to the links during construction of the chain.
With respect to an annular shaped link and using round solid or tubular wire, historically, rope chains have been formed using what has been referred to as a 3:1 ratio. This refers to the ratio of the inner diameter of the link to the thickness of the wire. With the 3:1 ratio, three links would be intertwined and fit within the inner diameter of an initial link as they are woven together. Thereafter, for a 3:1 ratio, a fourth link would then come along and be intertwined into the other three and such would start the beginning of a next series of again three links inserted into that link.
It should be appreciated, that in order to fit three links into an inner diameter, the inner diameter must be slightly greater than three times the thickness of each of the wires forming the link. Typically, the actual ratio may be in the neighborhood of 3.4-3.7:1. However, since it is understood that some additional room must be permitted to accommodate manipulation, the ratios are still referred to as 3:1 ratio. It should be understood, however, that hereinafter whenever ratios are given that the ratios are slightly greater to accommodate manipulation room.
Each of the links being utilized to form the rope chain has a gap formed along its surface extending between the outer periphery and the inner periphery. In the 3:1 ratio, the links are assembled alternately with one link having its gap in the up position and thereafter the next link being inserted with its gap 180xcex8 in opposition so that the gap is in the down position. This alternating relationship continues throughout the assembly. After all of links in the entire chain have been assembled, they are wrapped around a wire and alternating pairs of links are joined together typically using solder. Thus, two links are joined together and loosely connected between the next pair of links that are also joined together.
U.S. Pat. No. 4,651,517 provided an improvement on such historic 3:1 ratio by making the thickness of the wire diameter of the link smaller and the inner diameter larger, whereby it would be possible to achieve greater ratios such as 5:1, 7:1, etc. Thus, instead of placing three links within the inner diameter of another link, you would place five links or seven links within the inner diameter. Because of the thinner links, less material is used for each link. However, since the thickness of the wire used for each link is reduced, a greater number of links per fixed length would be needed with the higher ratios being used. Nevertheless, even though a greater number of links are required for a fixed length, because there is substantially less material in each link, there is a considerable saving in material using ratios of 5:1 or 7:1 or higher.
U.S. Pat. No. 4,651,517, however, is limited to odd ratios since it describes the same method of assembling the links wherein one link is inserted with its gap in the upright position and the next link is inserted with its gap approximately 180xcex8 opposed to the first gap. Thereafter, the links are assembled alternatingly with the gap being upward and the gap being downward.
U.S. Pat. No. 4,651,517 only identified odd ratios. Subsequently, U.S. Pat. No. 4,934,135 described a jewelry rope chain using even number ratios such as 4:1, 6:1, etc. In this arrangement, however, the assembly technique is modified so that certain groupings of adjacent links are inserted with their gaps in the same orientation and these links having their gaps with the same orientation are fixedly attached to one another to form a single group. This group is then attached to another one or another group of links with their gap in the opposite direction.
Despite both these patents, the bottom limit that has ever been utilized for forming jewelry rope chain has been the ratio of 3:1.
It is accordingly an object of the present invention to provide a jewelry rope chain with links having gaps which are interwoven to form a double helix configuration and having a ratio of less than 3:1 of link inner diameter to wire diameter.
It is a further object of the present invention to provide a jewelry rope chain having a ratio of less than 3:1 which requires less labor costs to assemble.
Yet another object of the present invention is to provide a jewelry rope chain having a ratio of inner diameter to wire thickness of less than 3:1 and which method of assembly can be applied to both hollow and solid rope chain, rope chains of different link size and shape, rope chains formed of different wire shapes, seam and seamless hollow rope chain, and both machine and manual assembly.
In accordance with the present invention, there is provided a jewelry rope chain having links which are interwoven together to form a double helix configuration. Each of the links have a cross section with the largest transverse distance across the cross section having a dimension dw. It should be appreciated that in the case of solid links this would be the cross section of the wire and in the case of hollow links this would be the cross section of the tubing used to form the link.
Each link also has an outer periphery and an inner periphery with a gap extending at one location between the outer periphery and the inner periphery. The inner periphery defines an interior space. The widest dimension of the interior space in a direction consistent with the direction of the gap has a dimension D, wherein D is less than three times dw. Thus, two links are placed within the interior diameter of a third link. It should be appreciated that in the case of an annular link, the dimension D would be the inner diameter of the link. In the case of round wire or tubing used to form the link, it would be the diameter across the wire or across the wire tubing which would be dw. However, link shapes other than annular could be used and wire or tubing cross sections other than round could also be used.
In forming the chain, pluralities of assemblies of links are connected in series. Each assembly comprises two adjacent links placed into the interior of a prior link, and an end link enveloping these two adjacent links. The two adjacent links have their respective gaps assembled in the same orientation and are fixed to each other to form a group. This group is then attached to the end link, which has a gap orientation about 180 degrees removed with respect to the gaps of the links in the group.
In the case of a hollow rope chain, it will be shown that the amount of precious metal, such as gold, needed for this ratio is about the same as the standard classic 3:1 ratio type of chain. The reason for this is that even though each link will be thicker and therefore have a greater amount of precious material in it, there are less links required in a fixed length of the chain so that the result is almost identical to that using a standard 3:1 ratio.
However, because there are a reduced number of links in a fixed length of the chain, there is considerable savings in labor costs. For example, there are approximately 20% less links which normally result in a savings of approximately 20% labor costs.
Furthermore, even in the case of solid links, where additional precious material would be used, there is still the cost savings cost. The gold, even though more is being used, is recoverable. The labor costs, unfortunately, are never recoverable and therefore the savings in labor result in a reduced cost for manufacturing.
Additionally, because the link will be thicker and a smaller interior space provided, the link will be stronger, thereby providing a stronger rope chain. Furthermore, because of the thicker link, when faceting the link or deforming it to from a simulated facet, the facet area will be larger thereby providing a more sparkling chain.